A Facile Method To Prepare Novel Ag₂O/Ag₂CO₃ Three-Dimensional Hollow Hierarchical Structures and Their Water Purification Function

Abstract

A facile, green, and low-cost method to prepare novel Ag 2 O/Ag 2 CO 3 three-dimensional hollow flowerlike hierarchical microspheres has been demonstrated. The microspheres were obtained by simple injection of Na 2 CO 3 aqueous solution into AgNO 3 ethanol solution. The surface morphology of the microspheres was relatively smooth, trumpet flowerlike hole, and flowerlike shallow hole when the reaction temperature was 8, 25, and 70 °C, respectively. They were assembled by nanoparticles. The microsphere prepared at 25 °C was composed of 86.3% Ag 2 CO 3 and 13.7% Ag 2 O. The HTEM image indicates that the Ag 2 CO 3 microsphere is wrapped by a thin Ag 2 O layer, and there is a heterojunction between Ag 2 CO 3 and Ag 2 O. The study of the formation mechanism demonstrates the first example of using water-soluble Na 2 CO 3 as templates to prepare 3D hierarchical microstructures. The Ag 2 O/Ag 2 CO 3 microspheres prepared at 25 °C have excellent adsorption and photocatalysis activity for Congo red (CR). The adsorption behavior of the Ag 2 O/Ag 2 CO 3 microsphere follows the Langmuir isothermal adsorption model. The maximal adsorption capacity of the Ag 2 O/Ag 2 CO 3 microsphere was about 100.84 mg g −1 for CR in water. Here, 87.5% of CR was removed within 20 min under visible light irradiation at an initial concentration of CR of 80 mg L −1 with a photodegradation rate constant, k, of 0.06814. The radicals (O 2 •− ,•OH) and hole (h + ) were proved to be the active species for photocatalyzing CR. The microspheres were reused five times without distinct loss of photocatalysis activity, which indicated that they have stable photocatalysis activity. KEYWORDS: One step, Na 2 CO 3 template, Hierarchical microspheres, Ag 2 O/Ag 2 CO 3 , Water treatment

In situ phase transformation synthesis of unique Janus Ag 2 O/Ag 2 CO 3 heterojunction photocatalyst with improved photocatalytic properties

“…3. The absorption band-edge of bare Ag 2 CO 3 extends from the UV to the visible region, corresponding to a band gap of 2.32 eV, consistent with previously reported data [20,37]. Importantly, an obvious improvement of the absorbance in the entire visible-light region is observed for the Janus nanocomposite when compared to the bare Ag 2 CO 3 absorption spectrum.…”

“…For instance, Yu et al [30] have reported an Ag 2 O/Ag 2 CO 3 heterostructure prepared by a phase transformation method and their results have indicated that the heterostructure interface is able to effectively hamper the recombination of photogenerated electrons and holes, leading to enhanced photocatalytic activity and stability. Very recently, Zhao et al [37] have reported Ag 2 O/Ag 2 CO 3 3-D hollow flower-like hierarchical microspheres, exhibiting improved photocatalytic performance and stability compared to those of bare Ag 2 CO 3 . Therefore, there has been great interest in design and development of tunable size and morphology based Ag 2 O/Ag 2 CO 3 heterostructure for efficient interface contact and charge separation in order to boost the photocatalytic performance and photostability.…”

Piezoelectric‐Effect‐Enhanced Full‐Spectrum Photoelectrocatalysis in p–n Heterojunction

“…The TiO 2 and TiO 2 /BTO nanorod absorbed UV light strongly, showing a sharp absorption peak and cutoff at around 380 nm (Figure d) . After the introduction of Ag 2 O, a shoulder peak appeared at ≈700 nm and the absorption extended to near‐infrared (NIR) region up to 1200 nm for TiO 2 /BTO/Ag 2 O . Thus, the full UV–vis–NIR photoelectrocatalysis could be expected to induce wide‐range PEC responses.…”

Ag2CO3 Decorating BiOCOOH Microspheres with Enhanced Full-Spectrum Photocatalytic Activity for the Degradation of Toxic Pollutants

“…Hence, the design of Ag 2 CO 3 -based heterojunction photocatalysts (e.g., Ag 2 CO 3 /Ag 2 O [28], Ag 2 CO 3 /Ag 2 S [29], Ag 2 CO 3 /Bi 2 MoO 6 [8,30], Ag 2 CO 3 /BiOCl [31], Ag 2 CO 3 /Ag/WO 3 [32] and Ag 2 CO 3 /AgBr/ZnO [33]) to improve the visible-light photocatalytic performance has been achieved by scholars. However, to the best of our knowledge, no Ag 2 CO 3 /BiOCOOH heterojunctions have been studied.…”